1. Field of the Invention
The present invention relates to an apparatus and method for transmitting and receiving a quasi-cyclic Low Density Parity Check (LDPC) code in a multimedia communication system, and more particularly to a quasi-cyclic LDPC code transmission and reception apparatus and method that support various codeword lengths and code rates.
2. Description of the Related Art
A multimedia communication system, for example, a Moving Picture Experts Group (MPEG) Media Transport (MMT) system provides various large-capacity content, such as High Definition (HD) content, Ultra High Definition (UHD) content, etc. Further, according to a diversification of this content and especially increases in large-capacity content, data congestion has become a more serious issue. As a result of the data congestion, content transmitted by a signal transmission device is not always completely transferred to a signal reception device, and some of the content is lost en route.
In general, data is transmitted on a packet basis, and accordingly, data loss is generated on a transmission packet basis. For example, if the transmission packet is lost on a network, the signal reception device cannot receive the lost transmission packet, and thus, cannot know the data within the lost transmission packet. As a result, user inconvenience occurs, such as audio quality deterioration, video quality deterioration, video break, caption omissions, file loss, etc.
Therefore, the MMT system may enhance system reliability using various error-control schemes in order to reduce information data loss that is often caused by an error that occurs on a network according to channel status. A typical example of an error-control scheme is an Application Layer-Forward Error Correction (AL-FEC) scheme.
However, a multimedia communication system, such as an MMT system, requires usage of a Forward Error Correction (FEC) code supporting a codeword length and a code rate, which vary according to a code rate and delay time required by a service.
Further, when a conventional AL-FEC scheme is used, a signal transmission and reception apparatus should use different FEC codes according to a codeword length and a code rate, thereby increasing the complexity of the MMT system.
Consequently, it is difficult to implement an MMT system due to this increased complexity.